San Francisco City Attorney Dennis Herrera has sent a cease-and-desist letter to Bird, Lime and Spin for operating their shared electric scooter programs in San Francisco.

“Despite previous warnings, your company LimeBike (“Lime”) has continued to operate an unpermitted motorized scooter rental program in the City and County of San Francisco (the “City”), creating a public nuisance on the City’s streets and sidewalks and endangering public health and safety,” City Attorney Herrera wrote specifically to Lime. “Lime must immediately cease and desist from unlawful conduct, as we provide further below.”

City Attorney Herrera wrote nearly identical letters to Spin and Bird. The letters say the companies have ignored warnings and operate in a way that is “creating a public nuisance on The City’s streets and sidewalks and endangering public health and safety.” Other complaints entail concerns of fall hazards and excessive use of public sidewalk space.

The letters also provide suggestions around ways to ensure people properly park the scooters. Each company has until April 30 to report back regarding how they’re going to address the complaints.

“We received the letter from the San Francisco City Attorney and we are taking his concerns and recommendations for improving Bird in San Francisco very seriously,” Bird spokesperson Kenneth Baer said in a statement to TechCrunch. “We are confident that by continuing to work with the city, we can build a framework that can make San Francisco a leader in bringing new mobility options that curb traffic and greenhouse gas emissions.”

Bird said it’s also going to start requiring riders to take a photo of where they park their Bird scooters.

“This will help Bird take action to ensure frequent violators of Bird’s parking rules are suspended or deactivated,” the Bird spokesperson said.

In the meantime, the Department of Public Works will continue to impound scooters that unlawfully block sidewalks.

Meanwhile, the SF Board of Supervisors’ Land Use and Transportation Committee heard proposed legislation and comments from the public pertaining to electric scooters today.

“We have been engaging with city officials since February and were the only ones to reach out proactively before there was any legislation or deployment,” a Spin spokesperson told TechCrunch. “We applaud city officials efforts to work with us in ensuring that we can bring environmentally-friendly transportation alternatives to San Francisco, and we support Supervisor Peskin’s legislation to regulate e-scooters and are eager to continue the conversations around these regulations. We are working to ensure that we comply with any of the outlined recommendations we don’t already have in place. As the only San Francisco-based company offering scooter share, it’s extremely important to us to continue working with the SFMTA, Board of Supervisors and community interest groups, such as Walk SF and the San Francisco Bicycle Coalition, to ensure that we’re addressing public concerns.”